Coolant in oil. Need help identifying cause.

This is sort of related to my other post regarding a cam swap. In the process of learning more about that process, it was discovered that the dumped oil contains a good amount of coolant. The results of the oil test can be found here. Suffice it to say, there is coolant in the oil. So I am now taking a detour on my way to a different cam as this issue will have to be addressed first.

I am looking for help identifying where the coolant may be seeping into the oil. I will do a pressure test tomorrow, but for now I have pulled the spark plugs out and stuck an endoscope into all the cylinders. The results are below. Note that the truck has not been driven or started in about 3 days prior to my doing this work.




Here are some picture from the endoscope. All pistons look about the same - pretty carboned up. Some, however, have what appears to be moisture. Can you guy draw any conclusions?